Implement osx:Variable element, w/some refactoring

[aw...@gmail.com]

Reviewers: shindig.remailer_gmail.com,

Message:
This patch implements <osx:Variable> for both data pipelining and
templating, as discussed on the opensocial spec group.

This required a bit of refactoring/cleanup in PipelinedData.  Most of
the interesting code in this patch is:
   - PipelinedData
   - PipelinedDataPreloader
   - VariableTagHandler

The patch also moves most of the tags into a templates.tags subpackage,
which accounts for most of the diffs.



Please review this at http://codereview.appspot.com/91118

Affected files:
   M      
java/gadgets/src/main/java/org/apache/shindig/gadgets/preload/PipelinedDataPreloader.java
   M      
java/gadgets/src/main/java/org/apache/shindig/gadgets/rewrite/TemplateRewriter.java
   M      
java/gadgets/src/main/java/org/apache/shindig/gadgets/spec/PipelinedData.java
   D      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/AbstractTagHandler.java
   D      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/AbstractTagRegistry.java
   D      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/CompositeTagRegistry.java
   D      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/DefaultTagRegistry.java
   M      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/DefaultTemplateProcessor.java
   M      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/ElementELResolver.java
   D      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/FlashTagHandler.java
   D      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/HtmlTagHandler.java
   D      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/IfTagHandler.java
   M      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/NullTemplateLibrary.java
   D      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/RenderTagHandler.java
   D      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/RepeatTagHandler.java
   D      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/TagHandler.java
   M      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/TagRegistry.java
   D      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/TemplateBasedTagHandler.java
   M      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/TemplateModule.java
   M      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/XmlTemplateLibrary.java
   A  +   
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/AbstractTagHandler.java
   A  +   
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/AbstractTagRegistry.java
   A  +   
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/CompositeTagRegistry.java
   A  +   
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/DefaultTagRegistry.java
   A  +   
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/FlashTagHandler.java
   A  +   
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/HtmlTagHandler.java
   A  +   
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/IfTagHandler.java
   A  +   
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/RenderTagHandler.java
   A  +   
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/RepeatTagHandler.java
   A  +   
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/TagHandler.java
   A  +   
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/TemplateBasedTagHandler.java
   A      
java/gadgets/src/main/java/org/apache/shindig/gadgets/templates/tags/VariableTagHandler.java
   M      
java/gadgets/src/test/java/org/apache/shindig/gadgets/preload/PipelineExecutorTest.java
   M      
java/gadgets/src/test/java/org/apache/shindig/gadgets/preload/PipelinedDataPreloaderTest.java
   M      
java/gadgets/src/test/java/org/apache/shindig/gadgets/rewrite/PipelineDataGadgetRewriterTest.java
   M      
java/gadgets/src/test/java/org/apache/shindig/gadgets/rewrite/TemplateRewriterTest.java
   M      
java/gadgets/src/test/java/org/apache/shindig/gadgets/spec/PipelinedDataTest.java
   M      
java/gadgets/src/test/java/org/apache/shindig/gadgets/spec/ViewTest.java
   D      
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/AbstractTagHandlerTest.java
   D      
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/CompositeTagRegistryTest.java
   D      
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/DefaultTagRegistryTest.java
   M      
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/DefaultTemplateProcessorTest.java
   D      
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/FlashTagHandlerTest.java
   D      
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/HtmlTagHandlerTest.java
   D      
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/IfTagHandlerTest.java
   D      
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/RenderTagHandlerTest.java
   D      
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/RepeatTagHandlerTest.java
   D      
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/TemplateBasedTagHandlerTest.java
   M      
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/XmlTemplateLibraryTest.java
   A  +   
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/tags/AbstractTagHandlerTest.java
   A  +   
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/tags/CompositeTagRegistryTest.java
   A  +   
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/tags/DefaultTagRegistryTest.java
   A  +   
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/tags/FlashTagHandlerTest.java
   A  +   
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/tags/HtmlTagHandlerTest.java
   A  +   
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/tags/IfTagHandlerTest.java
   A  +   
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/tags/RenderTagHandlerTest.java
   A  +   
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/tags/RepeatTagHandlerTest.java
   A  +   
java/gadgets/src/test/java/org/apache/shindig/gadgets/templates/tags/TemplateBasedTagHandlerTest.java
   M      
java/server/src/test/java/org/apache/shindig/server/endtoend/EndToEndTest.java
   M     java/server/src/test/resources/endtoend/pipeliningTest.xml